Adaptation to climate change in the countries of - Mekong River ...

Adaptation to climate change in the countries of the Lower Mekong Basin
Information on the potential impacts of climate change has been drawn from the National
Report and the Initial National Communication to the UNFCCC (MOSTE, 2000). A recent
study by FERs (FERs, 2008a) provides a scientific perspective on these impacts.
While total forest area is predicted to remain the same, the composition of forests, by type,
are expected to change markedly. In general, subtropical life zones are expected to decline,
while tropical life zones, toward the southern region of Thailand, are predicted to increase due
to expected intensification of precipitation. Subtropical dry forests, which currently occupy
1.2% of total forest area, might completely disappear and be replaced by tropical dry forests. A
new type of forest, tropical very dry forest, may also emerge in the north and the northeast areas
of the country (MOSTE, 2000; Chantragoon, 2007; Thangtham, 2007).
Rice grown under rain-fed conditions in Thailand was found to be highly vulnerable to
climate change. The results, which were based on climate data from four GCMs, suggest similar
declining trends in rice and maize yields over time. Their magnitudes, however, vary depending
on climate conditions, soil types and crop practice. Maize yields, for example, could drop from
5% in Nakhon Sawan province to 44 percent in Nakhon Ratchasima province. The impacts
on rice yields could be even more extensive and diverse. Rice yields could drop by 57% in
Roi-et province, but increase by 25% in Surin. The four climate models also demonstrated that
climate change could increase temperature in areas during the flowering period of crops by 1
to 7ºC. This will reduce flowering and harvesting periods as well as crop yields in general. In
general, the vulnerability of agriculture to climate change varies according to crops and location
characteristics, in addition to the climate conditions (Kerdsuk et al., 2004; Kerdsuk et al., 2007;
Bhaktikul, 2008; Jintrawet and Prammanee, 2005; Jintrawet, 2007).
Conflicts over the allocation of surface water in Thailand have now become a critical
issue due to the expansion of demand and a shortage of supply. Variations in the frequency
and intensity of rainfall in a monsoon region like Thailand also have imposed high risks of
drought and flood in the dry and wet seasons respectively. Climate change alters precipitation
patterns and potentially increases temperature. Changing rainfall patterns, in turn, affect the
level and intensity of surface runoff, while increasing temperature increases the rate of evapotranspiration
and hence reduces the water storage capability of the rivers and reservoirs. For
example, a case study of the potential climate change impact on water storage capacity of
the reservoir of the Sri Nakarin Dam, found that doubling CO 2 levels could result in possible
shortages of water in the watershed area above the Sri Nakarin Dam in 10 to 15 years, unless
water management is improved. While this dam is located outside the boundary of the LMB,
similar conclusions can be drawn for water resources within the LMB (Kongjan, 2008). The
most notable impacts of the climate change scenarios on water resources are variations in
precipitation and their intensity in different regions. More extreme flooding and drought could
emerge. The impacts on water resources could affect agricultural development substantially.
Lower water levels in the dams require serious water resource management. Crop yields and
cropping pattern could be severely affected. Hydropower development schemes are considered
as possible solutions to these problems even though they may have transboundary effects
(Thai Net, 2009; FERs, 2008b).
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